Lubricant compositions

ABSTRACT

A LUBRICANT COMPRISING (1) A LUBRICATING OIL (2) AN OIL SOLUBLE SUCCINIMIDE DISPERSANT AND (3) AN OIL SOLUBLE ALCOHOL OR ESTER HAS INCREASED DISPERSANCY PROPERTIES.

United States Patent U.S. Cl. 25251.5 A Claims ABSTRACT OF THEDISCLOSURE A lubricant comprising (1) a lubricating oil (2) an oilsoluble succinimide dispersant and (3) an oil soluble alcohol or esterhas increased dispersancy properties.

This invention relates to lubricant compositions having increaseddispersancy properties. More particularly it relates to lubricantcompositions in which the dispersancy effect of a succinimide dispersantadditive is increased by the presence of an oil soluble alcohol orester.

BACKGROUND OF THE INVENTION With the advent and ever increasing amountof tumpike driving and its continuous high speeds, and high enginetemperature, the deposition on engine parts of oil-insoluble particleshas become an extremely serious problem. This is generally true of allmodern, high performance internal combustion engines. Therefore, thesubject of this invention is a lubricant capable of maintaining theseinsoluble particles as a suspension in the oil to minimize theirdeposition and maintain the cleanliness of vital engine parts.

Succinirnide dispersant additives are known for dispersing insolublesformed during use of lubricating oils. It has now been found that thedispersancy effect of a succinimide dispersant additive can be increasedby the preseriilce of an alcohol or ester additive in the lubricating oSUMMARY OF THE INVENTION According to the present invention, therefore,a lubricant comprises a lubricating oil; an oil soluble succinimidedispersant additive that is a reaction product of a polyamine reactantand a succinic acid reactant; and an oil soluble alcohol or esteradditive. These components are defined below.

The lubricating oil is mineral or synthetic in orgin. It can be a blendof mineral and/or synthetic lubricating oils. Mineral lubricating oilscan be refined from aromatic, asphaltic, naphthenic, paraflinic or mixedbase crudes. The refining can give distillate lubricating oils andresidual lubricating oils (for example bright stocks), which can beblended to give convenient blends. Synthetic lubricating oils can bepolyolefins (for example a polyisobutene), but are preferably esterlubricating oils.

Ester lubricating oils are well known and comprise at least one esterthat is a reaction product of a monohydroxy alcohol and a monocarboxylicacid; at least one ester that is a reaction product of at least onemonohydroxy alcohol and a polycarboxylic acid; or at least one esterthat is a reaction product of a polyhydroxy alcohol and at least onemonocarboxylic acid. Mixtures of the ice esters can be used. Manydifferent synthetic esters and mixtures of esters are availablecommercially and need not be described further.

For the succinimide dispersant additive, the polyamine reactant is atleast one polyamine of the general formula (wherein R and R are alkylenegroups having up to 7 carbon atoms or alkyl substituted alkylene groupshaving up to 7 carbon atoms; R and R are hydrogen atoms, alkyl groupshaving up to 7 carbon atoms, or amino substituted alkyl groups, theamino substituents including alkylene diamine or polyalkylene polyaminegroups in which the alkylene group has up to 7 carbon atoms; and n is 0to 5). The polyamine reactant preferably has primary, secondary andtertiary basic nitrogen atoms. Examples of polyamine reactants arealkylene-diamines (for instance ethylenediamine, propylenediamine,butylenediamine or pentylenediamine); polyalkylene-polyamines (forinstance diethylenetriamine, triethylenetetramine,tetraethylenepentamine, pentaethylenehexamine, di(methylethylene)triamine, dibutylenetriarnine, tributylenetetramine ordipentylenehexamine); dialkylaminoalkylamines (for instancedimethylaminomethylamine, dimethylaminoethylamine,dimethylaminopropylamine or di methylaminobutylamine); primary,secondary, tertiary amines (for instance tris (2-imino-4-aminobutyl)amine). Convenient polyamine reactants are mixtures of polyethylenepolyamines, especially those containing tetraethylene pentamine. Suchmixtures are conveniently prepared by reacting ethylene dichloride withammonia.

The succinic acid reactant can be a succinic acid or a functionalderivative, for example the acylhalide, anhydride or ester. The succinicacid reactant has a substantially aliphatic hydrocarbon group linked toa methylene carbon atom. This group has 30 to 200 carbon atoms. It ispreferably a C alkylene polymer group, for example a polymeric group ofethylene, propylene l-butene, 2- butene or isobutene. The polymericgroup conveniently has a molecular weight of 400 to 3,000, preferably900 to 1,200 (calculated). Preferred polymeric groups are of isobutene.When it is desired to use a functional derivative of the succinic acid,the anhydride is most convenent. It can be made by reacting thepolymerized alkylene hydrocarbon with maleic anhydride.

In the reaction between the succinic acid reactant and the polyaminereactant, there can be formed amides, diamides, imides and diimides.Convenient mole ratios of succinic acid reactant to the polyaminereactant are 0.5/1 to 2.5/1. Products of the reaction are availableunder the trademarks Lubrizol 894 or Oronite 1200. They have aboutweight of reaction product in a hydrocarbon carrier oil. For a lubricantof the present invention, there is conveniently 0.2 to 10 (preferably0.5 to 5) percent weight of succinimide dispersant additive based on thelubricant.

The alcohol or ester additive of a lubricant of the pres ent inventionhas a boiling point such that it will either not distill orsubstantially not distill from the lubricant during use. The boilingpoint is preferably at least 200 C. (particularly at least 280 C. atatmospheric pressure). The alcohol or ester additive is monomeric and isnot a polymer. It preferably has a molecular weight of 100 to 2,500(calculated). The alcohol or ester additive can be incorporated as suchor as a concentrate. If desired, it can be added with other materials tobe added to a lubricant of the invention. Conveniently, there is 0.2 to10 (preferably 0.5 to percent weight of alcohol or ester additive basedon the lubricant.

The alcohol additive can be at least one monohydroxy or polyhydroxyalcohol. If desired, it can have thio atoms, for example it can bethiapentacosanol. The monohydroxy alcohols are conveniently aliphaticalcohols and may be unsaturated. These alcohols preferably have at least9 and more preferably at least 12 carbon atoms. Examples of preferredaliphatic monohydroxy alcohols are 2-methyl-7-ethyl-undecan-4-ol;dodecanol; tridecanol; tetradecanol; pentadecanol and oleyl alcohol.Further examples of aliphatic monohydroxy alcohols are included amongmonohydroxy alcohols of the general formula (wherein R is an alkyl,cycloalkyl, aryl or aralkyl group; R, and R are each a hydrogen atom oran alkyl, cycloalkyl, aryl or aralkyl group; and R R and R or any two ofthese symbols, can jointly be part of a ring). The aliphatic monohydroxyalcohols are conveniently those in which R R, and R are each alkylgroups, and R is a methyl group. These alcohols preferably have 9 to 11,12 to 15 or 15 to 19 carbon atoms. A mixture of them can be called amixture of C C or C1549 branched chain alkyl alcohols. The monohydroxyalcohols of the general formula which are not aliphatic are alsoexamples of suitable monohydroxy alcohols. When the alcohol is apolyhydroxy alcohol, it is conveniently a dihydroxy alcohol having atleast 5 carbon atoms (for instance hexan-l,6-diol); a trihydroxy alcohol(for instance trimethylol propane or glycerol); a tetrahydroxy alcohol(for instance pentaerythritol); or a hexahydroxy alcohol (for instancedipentaerythritol or a hexose such as mannnitol or sorbitol). Preferredalcohols melt below 40 C.

The ester additive can be at least one ester of a low molecular weightmonocarboxylic or polycarboxylic acid (e.g. C -C preferably C -C and arelatively high molecular weight alcohol, C upwards, preferably Calcohol such as Dobanol or Alfol 20+1. It is not desirable that it be anester of a natural straight chain C1240 aliphatic fatty acid, forexample oleic acid. An

ester additive for the present invention can be a reaction 1 product ofa monohydroxy or polyhydroxy alcohol or a phenol with a monocarboxylicor polycarboxylic acid. The monohydroxy alcohols are preferablyaliphatic. Examples are among aliphatic alcohols described earlier abovefor preparing ester lubricating oils. The monocarboxylic orpolycarboxylic acid can be aliphatic, cycloaliphatic or aromatic.Examples are among the carboxylic acids described earlier above forpreparing ester lubricating oils. Preferred carboxylic acids arenaphthenic acids and alkyl substituted .benzoic, salicylic, resorcylic,anthranilic or naphthoic acids. The esters conveniently have at least 10carbon atoms. Preferred esters melt below 70 C. Examples of esters whichmay be employed according to the invention are those produced by thereaction of isobutyric acid and primary aliphatic straight chainalcohols having at least twenty carbon atoms (Alfol 20+) and thereaction of salicylic acid and a mixture of such alcohols having from 12to 15 carbon atoms (Dobanol 25). A lubricant of the present inventioncan also comprise one or more supplementary additives, the amounts beingappropriate to the effects desired. Examples are: (a) Antifoam agents,for instance silicones;

(b) Antioxidants, for instance diarylamines (such asp,p'-dioctyldiphenylamine); substituted amines (such as phenyl anaphthylamine); substituted phenothiazines (such asN-substituted-3,7-dialkyl phenothiazines); substituted phenols (such as4,4'-rnethylene-bis (2,6-di-t-butyl phenol; metaldi-alkyldithiocarbamates metal dialkyldithiophosphates (such as zincdialkyldithiophosphate);

(c) Anticorrosion agents, for instance Group II-A metal salts ofpetroleum sulfonic acids (such as a calcium 1 petroleum s-nl-fonate),especially basic form of such salts; or alkenyl succinic acids or theiranhydrides;

(d) Detergents, for instance Group H-A metal salts of naphthenic acids(such as a basic calcium naphthenate), or such salts of alkyl salicylicacids) such as a mixture of calcium C1448 alkyl and dialkylsalicylates); or Group II-A metal phenates (such as a calcium salt of acondensation product of formaldehyde and octyl phenol);

(e) Extreme pressure agents, for instance organic phosphorus containingcompound, such as phosphorothionates (for exampletriphenylphosphorotbionate); phosphates (for example triphenylphosphateor tricresylphosphate); salts of chlorinated unsubstituted phosphonicacids with amines; metal dialkyldithiocarba'amtes (such as zincdialkyldithiocarbamates); metal dialkyldithiophosphates polyphenyls (forexample chlorinated diphenyls), such as those sold under the trademarkAroclor;

(f) Metal passivators and corrosion inhibitors, for instance triazoles(such as 1,2,3-benztriazole; methyl-1,2,3- benztriazole; 3 amino 5phenyl 1,2,4-triazole; or 3 amino 5 anilido 1,2,4 triazole); ordicarboxylic acids (such as sebacic, azelaic or adipic acid, which areparticularly useful as inhibitors of lead corrosion);

[(g) Pour point depressants, for instance polymers of esters of acrylicacid or an alkylacrylic acid;

(h) Thickeners, for instance polyisobutenes; polymers of esters ofacrylic acid or an alkylacrylic acid (such as lauryl methacrylate);esters of polyoxaalkylene glycols (such as fluids sold under thetrademark Ucon or copolymers of propylene oxide and ethylene oxide soldunder the trademark Oxilube.

The invention is illustrated by the following examples.

Example I TABLE 1 Additives: Viscosity, cs./60 C.

2% weight polyisobutenyl succinimide (Lubrizol 894) 49.6 1% weightthiapentacosanol 47.3

2% weight polyisobutenyl succinimide (Lubri-' 201 894) +1% weightthiapentacosanol 42.1

1% weight methyl salicylate 46.2 2% weight polyisobutenyl succinimide(Lubrizol 894) +1% weight methylsalicylate 43.1

EXAMPLE I! A mineral lubricating oil blend having a viscosity of 30 cs.at 60 C. was used in a commercial diesel engine until contaminated to4.5% w. insolubles (viscosity now 49.6 cs. at 60 C.) and to thecontaminated oil were added 2% W. polyisobutenyl succinimide (Lubrizol894) and 1% w. of one of the following additives. The viscosities of theresulting composition were determined in Example I.

Methyl ester of ternary or quaternary monocarboxylic acids having atleast 16 carbon atoms (Versatic 16 acids) 40.0

Methyl naphthenate mixture of primary C C alcohols Dobanol 25) Mixtureof primary C -C alcohols (Dobanol -25) salicylate (described above) 42.1Mixture of primary C -C alcohols (Dobanol 25) 42.7 iDinonyl phthalate42.5

.Di-2-ethyl hexylazelate Z-ethylhexyl ester of ternary or quaternaryunonocarboxylic acids having at least 10 carbon atoms (Versatic 10acids) 40.0

Example III Road tests in a commercial diesel powdered automobile, usinga lubricant composition according to the invention (and a control) werecarried out, involving viscosity and insolubles determinations at 800km. intervals. The following results were obtained:

COMMERCIAL LUBRICANT COM- POSITIONS (CLC) CLO plus 1% w. C12- C15primary straight chain aliphatic (Do bauol) salicylate CLC plus 1% W.Cn-

Cn primary straight chain aliphatic (Dobanol) stearate CLC plus 1% w.thiapentacosanol The commercial lubricant composition employed in theseexamples consisted of a base oil blend of HVI solvent refined oilscontaining a combination of additives comprising superbasic alkalineearth metal alkyl salicylates, polyisobutenyl succinimide and zincdialkyl dithiophosphate.

We claim as our invention:

1. A lubricant composition consisting essentially of a major amount of alubricating oil and (a) from about 0.2% to about 10% by weight of thecomposition of an oil-soluble alkenyl succinimide dispersant additivethat is the reaction product of one mole of a polyamine reactant of theformula wherein -R and R are alkylene groups having up to 7 carbon atomsor alkyl substituted alkylene groups having up to 7 carbon atoms; R and\R are hydrogen atoms, alkyl groups having up to 7 carbon atoms, oramino substituted alkyl groups in which the amino substituents arealkylene diamine or polyalkylene polyamine groups where the alkylenegroup has up to 7 carbon atoms; and n is 0 to 5, and from 0.5 to 2.5moles of an alkenyl succinic acid reactant having 30 to 200 carbon atomsin the alkenyl group and -(b) from about 0.2% to about 10% by weight ofthe composition of an oil-soluble monomeric monohydroxy alcohol additivehaving at least 9 carbon atoms of the formula Ra Rr-(EJ CIEDOH in whichR is an alkyl, cycloalkyl, aryl or aralkyl group; R and R are each ahydrogen atom or an alkyl, cycloalkyl, aryl or aralkyl group; and R Rand [R or any two of these can jointly be part of a ring, or anoilsoluble monomeric ester additive that is the reaction product of a C-C monocarboxylic acid and an alkanol having suificient carbon atomssuch that the molecular weight of said ester is at least 100.

2. The composition of claim 1 in which the alkanol reactant used inproducing the oil soluble ester additive has from 12 to 20 carbon atoms.

3. The composition of claim 1 in which the oil soluble alcohol or esteradditive has a boiling point greater than 200 C.

4. The composition of claim 1 in which the reaction product of thepolyamine reactant and the alkenyl succinic acid reactant ispolyisobutenyl succinimide.

5. The composition of claim 4 in which the polyisobutenyl succinimideforms 2% by weight of the composition and the oil soluble alcohol orester additive forms 1% by weight of the composition.

6. The composition of claim 1 in which the oil soluble alcohol or esteradditive forms from about 0.5% to about 5% by weight of the composition.

7. The composition of claim 6 in which the acid from which the solubleester additive is derived is a naphthenic, salicylic, resorcylic,anthranilic, naphtholic or alkyl substituted 'benzoic acid.

8. The composition of claim 6 in Which the oil soluble additive containsat least twelve carbon atoms.

7 8 9. The composition of claim 1 in which the alkanol 3,331,776 7/1967Krukziener 252-56 reactant used in producing the oil-soluble esteradditive 3,381,022 4/1968 Le Suer 25256 R has at least 8 carbon atoms.3,405,065 10/ 1968 Goodwine 252-515 A References Cited 5 DANIEL E.Primary Examiner UNI STATES PATENTS W. J. SHINE, Assistant Examiner3,202,678 8/1965 Stuart et al 25251.5 A Us 3,219,666 11/1965 Norman (ital. Z5251.5 A 252 52 56 R, 57 V 3,288,714 11/1966 Osuch 25257 0

